Timber & Framing Lumber Calculator — Linear Metres and Feet
Calculate linear metres or linear feet of timber for any framing project — wall plates, rafters, battens, joists and noggins. Enter lengths, quantities and cross-sections to get a full cut list with total length and estimated weight.
What is a linear metre — or linear foot — of timber?
Length alone, with the cross-section ignored. A 4.8 m length of 48 × 98 is 4.8 linear metres, and so is a 4.8 m length of 48 × 148; a 16 ft 2×4 is 16 linear feet, the same as a 16 ft 2×6. The price per metre or foot differs, the measurement does not — which is why each size is counted separately.
How do I work out the lumber for a frame?
List every member type with its section, quantity and length; multiply quantity × length for that line's linear metres or feet; total the lines. Add 10–15% for cuts and selection, and round each size up on its own — a 3 m stud cannot be made from 2.4 m offcuts, and a 10 ft one cannot come from 8 ft stock.
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How the framing lumber calculator works
- 1Enter each timber type with cross-section — e.g. 48×98 mm, or a nominal 2×4 that measures 1½ × 3½ in (38×89 mm) dressed — plus quantity and individual length
- 2Linear metres, or linear feet, per line item: quantity × length
- 3Total linear metres or feet: sum of all line items
- 4Weight: cross-section area × length × timber density (typically 500 kg/m³, or about 31 lb/cu ft, for softwood)
- 5Add 10–15% waste for cuts, splits and selection
- 6Timber is sold by the running metre or the linear foot — round up each line item independently
Worked example
Roof structure: 12 rafters at 4.2 m (14 ft), 6 ridge board pieces at 2.4 m (8 ft), 24 noggins at 0.6 m (2 ft). All 48×98 mm C24 timber — the European equivalent of a 2×4.
Rafters: 50.4 lm. Ridge: 14.4 lm. Noggins: 14.4 lm. Total: 79.2 lm — 260 linear feet. With 10% waste: 87.2 lm, or 286 lf. Estimated weight: 207 kg (456 lb).
Frequently asked questions
What timber size should I use for rafters?
Rafter size depends on span and spacing. For a 3 m (10 ft) rafter span at 600 mm centres — 24 in OC — in C24 softwood, 47×150 mm, a nominal 2×6, is typically sufficient. Always consult span tables or a structural engineer for roof design.
What is C16 vs C24 timber?
C16 and C24 are strength grades for softwood. C24 is stronger and stiffer — required for most structural applications (rafters, joists, studs in load-bearing walls). C16 is acceptable for non-structural use.
How much does a linear metre of 47×100 mm timber weigh?
At 500 kg/m³ (31 lb/cu ft) average density: 47×100 mm = 0.0047 m² cross-section. Per metre: 0.0047 × 500 = 2.35 kg/lm — about 1.6 lb per linear foot. A 4.2 m (14 ft) rafter weighs approximately 9.9 kg, or 22 lb.
What is the difference between sawn and planed timber?
Sawn (regularised) timber has rough surfaces and is slightly oversized — 47×100 mm sawn gives approximately 45×97 mm actual. Planed timber (PAR/CLS) has smooth surfaces and is smaller. US lumber works the same way: a nominal 2×4 measures 1½ × 3½ in (38×89 mm) once dressed. Always check actual dimensions.
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